JP2009233891A - Inkjet recording apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a period of time required for double-side recording by effectively using the recording time of an image for the first surface of a recording paper sheet, as the drying time of ink stuck to the first surface. <P>SOLUTION: A first image to be recorded on the first surface of the recording paper sheet is bisected in a forward direction being the conveying direction of the recording paper sheet in recording, to set front and rear half regions. Front-side ink volume and rear-side ink volume being ink volume necessary for recording the image of each region on the first surface are obtained and compared. A first double-side recording process or a second double-side recording process is selected according to the result of the comparison. The first double-side recording process is selected when the front-side ink volume is larger than the rear-side ink volume and the recording of the first image is started from the front half region. The second double-side recording process is selected when the rear-side ink volume is larger than the front-side ink volume, the first image is rotated by 180° and the recording of the first image is started from the rear half region. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inkjet recording apparatus and method for recording an image on both sides by inverting a recording medium.

  2. Description of the Related Art An ink jet recording apparatus that records an image by attaching ink droplets ejected from nozzles of an ink jet head to recording paper (hereinafter referred to as droplet ejection) is known. Also known is an ink jet recording apparatus that performs double-sided recording by inverting the front and back surfaces of a recording sheet. A conventional inkjet recording apparatus capable of double-sided recording, for example, transports a recording sheet in the forward direction and ejects ink droplets onto the surface (first surface) of the recording sheet to record a first image. After the ink adhering to the first surface is dried, the recording paper is conveyed in the reverse direction opposite to the forward direction to invert the front and back surfaces. The recording paper is conveyed again in the forward direction, and a second image is recorded by ejecting ink droplets onto the back surface (second surface) of the recording medium.

  The reason why the drying time is provided after image recording on the first surface is that when the recording paper is reversed before the ink deposited on the first surface is dried and fixed, the roller or guide in contact with the first surface is used. This is because the first image is disturbed. Further, there is an effect of preventing the recording paper used at the time of the next image recording from being stained by the ink adhering to the roller or the guide.

  In the conventional ink jet recording apparatus, the drying time is set long so that the ink ejected onto the first surface is reliably dried and fixed and then the recording paper is reversed. However, since a uniform drying time is applied even to an image with a small ink droplet ejection amount, there is a problem that the recording time becomes long. In order to solve this problem, an ink jet recording apparatus described in Patent Document 1 has been invented. In the ink jet recording apparatus, the amount of ink ejected onto the first surface of the recording paper is counted, and the drying time is determined based on the count value.

When the ink is locally concentrated and ejected, drying and fixing are slower than when the ink is dispersed and ejected. However, in Patent Document 1, since it is not possible to determine whether ink is dispersed and ejected in a localized manner or locally concentrated, it is not possible to determine whether the ink on the first surface is undried. Was sometimes reversed. In order to solve this problem, an ink jet recording apparatus described in Patent Document 2 has been invented. In the ink jet recording apparatus, an image recorded on the first surface is divided into a plurality of regions, the ink droplet ejection amount in each region is counted, and the drying time is set based on the count value.
US Pat. No. 6,149,327 JP 2005-125750 A

  Drying and fixing of the ink ejected onto the recording paper starts immediately after the ink ejection. In other words, the ink that has been ejected onto the leading edge of the recording paper can use the time during which the image is recorded up to the trailing edge of the recording paper as the drying time. In the invention described in Patent Document 2, the drying time is set in accordance with the position of the divided area of the image with a large amount of ink droplet ejection. However, since the image recording direction is always constant, the image recording time is effective as the drying time. Not available.

  An object of the present invention is to effectively use the recording time of the image on the first surface of the recording paper as the drying time of the ink attached to the first surface, thereby shortening the time required for double-sided recording.

  The ink jet recording apparatus of the present invention divides the first image into the front end half area and the rear end half area in the forward direction, and the front end ink hitting, which is the amount of ink droplets necessary for recording the image in each area. Ink drop amount acquisition means for acquiring the drop amount and the trailing edge side ink drop amount is provided. Further, a recording control means is provided for comparing the amount of ink ejected on the front end side and the amount of ink ejected on the rear end side, and controlling the recording of the first image and the second image based on the comparison result. The recording control means rotates the first image and the second image by 180 ° to record on the first surface and the second surface when the front-side ink droplet ejection amount is smaller than the rear-end side ink droplet ejection amount. Yes.

  Another ink jet recording apparatus of the present invention includes an ink droplet ejection amount acquisition unit and a recording control unit, similarly to the above ink jet recording apparatus. However, when the front-end side ink droplet ejection amount is smaller than the rear-end side ink droplet ejection amount, the recording medium is once transported in the forward direction and passed through the inkjet head, and then the recording medium is transported in the reverse direction to The first image is recorded on the first surface by the head, which is different from the above-described ink jet recording apparatus.

  The ink droplet ejection amount acquisition unit may acquire the first ink droplet ejection amount and the second ink droplet ejection amount that are necessary for recording the first image and the second image. In this case, the first ink droplet ejection amount and the second ink droplet ejection amount are compared by the recording control means. When the first ink droplet ejection amount is larger than the second ink droplet ejection amount, the first image and the second image are printed. Are preferably replaced.

  You may provide the drying time calculation means which calculates the drying time when the ink adhering to the 1st surface dries based on the front end side ink droplet amount and the rear end side ink droplet amount.

  The ink jet recording method of the present invention divides a first image into a front end side half area and a rear end side half area in the forward direction in which the recording medium is conveyed, and a droplet amount of ink necessary for recording an image in each area An ink droplet ejection amount acquisition step of acquiring the leading edge side ink droplet ejection amount and the rear end side ink droplet ejection amount. In addition, a comparison process is provided in which the front-side ink ejection amount and the rear-end side ink ejection amount are compared, and either the first double-sided recording step or the second double-sided recording step is selected according to the comparison result. Yes.

  The first double-sided recording process is selected when the front-end side ink droplet ejection amount is larger than the rear-end side ink droplet ejection amount. In the first double-sided recording step, the first image is recorded on the first side while conveying the recording medium in the forward direction. After the recording medium is reversed, the second image is recorded on the second surface while the recording medium is conveyed in the forward direction again.

  The second double-sided recording process is selected when the front end side ink droplet ejection amount is smaller than the rear end side ink droplet ejection amount. In the second double-sided recording step, the first image is rotated by 180 ° and recorded on the first surface while the recording medium is conveyed in the forward direction. After the recording medium is reversed, the second image is rotated by 180 ° and recorded on the second surface while the recording medium is conveyed in the forward direction again.

  Another ink jet recording method of the present invention includes an ink droplet ejection amount acquisition step, a comparison step, a first double side recording step, and a second double side recording step, as in the above ink jet recording method. However, the second double-sided recording step is different from the ink jet recording method. In the second double-sided recording process of the present invention, the recording medium is once transported in the forward direction and passed through the ink jet head, then the recording medium is transported in the reverse direction, and the first image is recorded on the first surface by the ink jet head. ing. Further, after the recording medium is reversed, the second image is recorded on the second surface while the recording medium is conveyed in the forward direction.

  Prior to the ink droplet ejection amount acquisition step, the first ink droplet ejection amount and the second ink droplet ejection amount necessary for recording the first image and the second image are acquired, and the first ink droplet ejection amount and the second ink droplet ejection amount are obtained. An image replacement step of comparing the first and second images when comparing the two ink droplet ejection amounts and the first ink droplet ejection amount being larger than the second ink droplet ejection amount may be provided.

  A drying time calculating step of calculating a drying time for drying the ink attached to the first surface based on the leading-end side ink droplet amount and the trailing-end side ink droplet amount may be provided.

  According to the present invention, since the recording of the first image is started from the area where the ink droplet ejection amount is large, of the front end side half area and the rear end side half area of the first image, The recording time can be used as the drying time of the area where recording has started. Accordingly, it is possible to shorten the drying time until the reversal of the recording medium is started after the recording of the first image is completed, and it is possible to shorten the time required for double-sided recording.

  Since the first image and the second image are switched when the first image is recorded from the area where the ink droplet ejection amount is large, the first image recorded on the first surface and the second surface of the recording medium are switched. The orientation of one image and the second image can be matched.

  In addition, when recording the first image from an area with a large amount of ink droplet ejection, the first image is recorded while transporting the recording medium in the reverse direction, so that the recording direction of the image is fixed. The first image can be recorded on the paper in an appropriate direction.

  Since the first image and the second image are interchanged according to the amount of ink droplet ejection of the first image and the second image, an image with a small ink droplet ejection amount is recorded as the first image. The drying time of the ink attached to the surface can be further shortened.

  The ink jet recording apparatus 2 shown in FIG. 1 has a double-sided recording function for recording images on the first surface 3a and the second surface 3b, which are both surfaces of the recording paper 3. The ink jet recording apparatus 2 includes a box-shaped housing 4 and a paper feeding unit 5, a transport unit 6, a recording unit 7, a paper discharge unit 8, and a recording paper reversing unit 9.

  The paper feed unit 5 provided on the back side of the housing 4 includes a paper feed tray 12 and a paper feed roller 13. The paper feed tray 12 is a plate-like member disposed at an inclination, and stores a plurality of recording papers 3 with the second surface 3b facing downward. The sheet feeding tray 12 is pivotally supported by a rotating shaft 14. The paper feed tray 12 is rotated between a standby position and a paper feed position by a transport motor 15 (see FIG. 2). The paper feed roller 13 faces the lower end side (front end side) of the first surface 3 a of the recording paper 3 stored in the paper feed tray 12. The paper feed roller 13 is rotated clockwise by the transport motor 15 when the recording paper 3 is supplied to the recording unit 7.

  When the paper feed tray 12 is in the standby position shown in FIG. 1, a gap is formed between the recording paper 3 on the paper feed tray 12 and the paper feed roller 13. When the paper feed tray 12 is rotated to the paper feed position in the clockwise direction, the recording paper 3 on the paper feed tray 12 contacts the paper feed roller 13. When the paper supply roller 13 rotates, the recording paper 3 is conveyed toward the conveyance unit 6 with the first surface 3a facing upward. A paper feed path 19 is formed by the guide member 18 between the paper feed tray 12 and the transport unit 6.

  The transport unit 6 includes a transport roller pair 21 and paper edge sensors 22a and 22b. The conveyance roller pair 21 includes a pair of rollers that are in pressure contact with each other, and one of them is rotated by the conveyance motor 15. The conveyance roller pair 21 sandwiches the recording paper 3 supplied from the paper supply unit 5 and conveys the recording paper 3 in the forward direction and the reverse direction (sub-scanning direction). The paper edge sensors 22a and 22b are, for example, reflection type optical sensors, and detect the leading edge and the trailing edge of the recording paper 3. The paper edge sensor 22a detects the recording paper 3 when transporting in the forward direction, and the paper edge sensor 22b detects the recording paper 3 when transporting in the reverse direction.

  The recording unit 7 includes a head unit 25 and a platen 26. The head unit 25 includes a carriage 27. The carriage 27 is supported movably in the main scanning direction by a guide rod 28 arranged in a main scanning direction (front and rear depth direction in FIG. 1) orthogonal to the sub-scanning direction (left and right direction in FIG. 1). The carriage 27 is moved in the main scanning direction by a carriage motor 29 (see FIG. 2). A plurality of ink cartridges 30 each storing ink of each color such as yellow (Y), magenta (M), cyan (C), and black (K) are set on the carriage 27.

  Under the carriage 27, for example, four inkjet heads 33 are provided in the main scanning direction. Each inkjet head 33 corresponds to each of the Y, M, C, and K ink cartridges 30. Each inkjet head 33 is provided with a number of nozzles and an ejection device that ejects ink droplets downward from each nozzle.

  The platen 26 is disposed below the head unit 25. The lower surface of the recording paper 3 is supported by the platen 26 when an image is recorded by ink droplets ejected from the head unit 25.

  The paper discharge unit 8 includes a paper discharge tray 36 and a pair of paper discharge rollers 37. The paper discharge tray 36 is a tray from which the recorded recording paper 3 is discharged. The paper discharge tray 36 serves as a switchback unit on which a part of the recording paper 3 is temporarily placed when the recording paper 3 conveyed in the forward direction is switched back and sent to the recording paper reversing unit 9. Is also used.

  The paper discharge roller pair 37 includes a pair of rollers that are in pressure contact with each other, and one of them is rotated by the transport motor 15. The paper discharge roller pair 37 sandwiches the recording paper 3 that has passed through the recording unit 7 and discharges it onto the paper discharge tray 36. Further, when the front and back surfaces of the recording paper 3 are reversed, the recording paper 3 is fed into the recording paper reversing unit 9 together with the conveying roller pair 21.

  The recording sheet reversing unit 9 includes a loop-shaped conveyance path 40, two sets of reversing roller pairs 41 and 42, a first switching guide 43 and a second switching guide 44. The loop-shaped conveyance path 40 is provided below the sheet feeding path 19 by the guide member 18. The loop-shaped conveyance path 40 is connected to both ends of the paper feed path 19. The reverse roller pair 41 is composed of a pair of rollers that are in pressure contact with each other, and one of them is rotated by the transport motor 15. The other pair of reversing rollers 42 has the same configuration.

  The first switching guide 43 and the second switching guide 44 are rotated between the paper feeding position and the reverse position by the transport motor 15. The sheet feeding path 19 is opened when the first switching guide 43 and the second switching guide 44 are at the sheet feeding position indicated by the solid line, and the recording sheet 3 can be fed. When the first switching guide 43 is in the reverse position indicated by the broken line, the rear end (the front end in the reverse direction) of the recording paper 3 switched back from the paper discharge tray 36 is brought into contact with the first switching guide 43 and guided to the loop conveyance path 40. When the second switching guide 44 is in the reverse position indicated by the broken line, the recording paper 3 conveyed through the loop-shaped conveyance path 40 is sent out to the paper supply path 19. The recording paper 3 passed through the recording paper reversing unit 9 and sent to the paper feed path 19 is inverted so that the second surface 3b faces up and the first surface 3a faces down.

  The paper feed roller 13, the transport roller pair 21, the paper discharge roller pair 37, and the reverse roller pairs 41 and 42 are rotated clockwise and counterclockwise by the transport motor 15. A drive transmission mechanism (not shown) is provided between the transport motor 15 and the paper feed tray 12, the first switching guide 43, and the second switching guide 44 to operate them at a predetermined timing.

  As shown in FIG. 2, the inkjet recording apparatus 2 includes a control unit 47 that controls each drive unit. The control unit 47 includes an MPU 48, a ROM 49, a DRAM 50, and a gate array 51. The MPU 48 performs various operations such as various calculations, discrimination, and control associated with image recording on the recording paper 3. The ROM 49 stores a program executed by the MPU 48. The DRAM 50 temporarily stores the input recording data and functions as a work area for arithmetic processing by the MPU 48.

  The control unit 47 is connected to an interface 54 for exchanging signals with an external device (not shown) such as a host computer. A signal input from the interface 54 is input to the MPU 48 and the DRAM 50 through the gate array 51.

  Connected to the control unit 47 are a head driver 57 that drives an ejection device provided in each nozzle of the inkjet head, a motor driver 58 that drives the transport motor 15, a motor driver 59 that drives the carriage motor 29, and the like. ing. For example, a pulse motor is used for the transport motor 15 and the carriage motor 29. Paper edge sensors 22 a and 22 b are connected to the control unit 47. An encoder 62 that detects the position of the carriage 27 in the main scanning direction is also connected to the control unit 47.

  As shown in FIG. 3, the gate array 51 is provided with a data conversion circuit 65 and an ink droplet ejection amount acquisition circuit 66. Recording data, which is image data for printing, is input to the gate array 51 via the interface 54. The data conversion circuit 65 converts the input recording data into Y, M, C, and K drive data. Each drive data is data for driving each of the Y, M, C, and K inkjet heads 33, and represents a position where ink droplets of each color are ejected.

  FIG. 4 is an example of the first image 69 recorded on the first surface 3 a of the recording paper 3. The left and right in the figure correspond to the forward direction and the reverse direction, which are the conveyance directions of the recording paper 3. When the first recording data recorded on the first surface 3a is sent from the interface 54, the ink droplet amount acquisition circuit 66 divides the first image 69 represented by the first recording data into two in the forward direction. In addition, a front end side half region 69a and a rear end side half region 69b are set. A two-dot chain line D is a line representing the division position of the front end side half area 69a and the rear end side half area 69b, and is not the first image 69, and therefore is not recorded on the first surface 3a.

  The ink droplet ejection amount acquisition circuit 66 uses the Y, M, C, and K drive data converted by the data conversion circuit 65 to transfer the images of the front end side half area 69a and the rear end side half area 69b to the recording paper 3. The leading-end side ink droplet ejection amount A and the trailing-end side ink droplet ejection amount B, which are the amount of ink droplets necessary for recording, are acquired.

  When gradation representation of an image is performed by the number of droplets ejected onto the recording paper 3, that is, the number of dots, the ink ejection amount is obtained by counting the number of dots in each of the areas 69a and 69b. Can do. When gradation representation is performed by changing the dot size together with the number of dots, the number of dots counted from each of the regions 69a and 69b is multiplied by a predetermined coefficient set according to the dot size. If so, the ink droplet ejection amount can be obtained.

  The MPU 48 operates as a recording control unit 72 and a drying time calculation unit 73 according to a program stored in the ROM 49. The recording control unit 72 compares the front-end side ink droplet ejection amount A acquired by the ink droplet ejection amount acquisition circuit 66 with the rear-end side ink droplet ejection amount B. The recording control unit 72 selects either the first double-sided recording step or the second double-sided recording step based on the comparison result of the ink droplet ejection amounts A and B.

  The first double-sided recording process is selected when the front-end side ink droplet ejection amount A is larger than the rear-end side ink droplet ejection amount B. In the first double-sided recording step, recording is started from the forward end of the first image 69. The second double-sided recording process is selected when the front end side ink droplet ejection amount A is smaller than the rear end side ink droplet ejection amount B. In the second double-sided recording step, recording is started from the rear end of the first image 69 in the forward direction.

  The drying time calculation unit 73 calculates the time until the recording paper reversing unit 9 starts reversing the front and back surfaces of the recording paper 3 after recording the image on the first surface 3 a of the recording paper 3. The drying time calculation unit 73 calculates the drying time based on the front end side ink droplet ejection amount A and the rear end side ink droplet ejection amount B acquired by the ink droplet ejection amount acquisition circuit 66. The drying time is calculated so that the recording time is used as part of the drying time.

  FIG. 5 shows an example of the second image 76 recorded on the second surface 3 b of the recording paper 3. 6 and 7 show a procedure in which the first image 69 and the second image 76 are recorded on the first surface 3a and the second surface 3b of the recording paper 3 by the first double-side recording step and the second double-side recording step. Shown schematically. The operation of the above embodiment will be described below according to the flowchart shown in FIG.

  The gate array 51 reads the first recording data sent via the interface 54 and stores it in the DRAM 50. The data conversion circuit 65 converts the first recording data stored in the DRAM 50 into Y, M, C, and K drive data, and stores the drive data in the DRAM 50.

  The ink droplet ejection amount acquisition circuit 66 divides the first image 69 represented by the first recording data into a front end side half area 69a and a rear end side half area 69b. From the drive data of Y, M, C, and K, the front end side ink droplet ejection amount A of the front end side half region 69a and the rear end side ink droplet ejection amount B of the rear end side half region 69b are obtained. The front end side ink droplet ejection amount A and the rear end side ink droplet ejection amount B are stored in the DRAM 50.

  The recording control unit 72 reads and compares the front-end side ink droplet ejection amount A and the rear-end side ink droplet ejection amount B from the DRAM 50 via the gate array 51, and compares the first double-sided recording step and the second double-sided recording step. Decide which one to use for duplex recording. The recording control unit 72 selects the first double-sided recording step when the front end side ink droplet ejection amount A is larger than the rear end side ink droplet ejection amount B, and the front end side ink droplet ejection amount A is equal to the rear end side ink droplet ejection. When the amount is smaller than the amount B, the second double-side recording process is selected.

  Hereinafter, the case where the first double-sided recording process is selected by the recording control unit 72 will be described with reference to the flowchart shown in FIG. The drying time calculation unit 73 calculates the drying time based on the front end side ink droplet ejection amount A and the rear end side ink droplet ejection amount B. The drying time is calculated so that the recording time of the first image 69 is used as part of the drying time. The calculated drying time is stored in the DRAM 50.

  The controller 47 controls the motor driver 58 to rotate the carry motor 15 and move the paper feed tray 12 to the paper feed position. The recording paper 3 on the paper feed tray 12 contacts the paper feed roller 13. The uppermost recording paper 3 is sent out to the paper feed path 19 by the clockwise rotation of the paper feed roller 13.

  The leading edge of the recording paper 3 conveyed in the forward direction by the paper supply roller 13 through the paper supply path 19 is sandwiched between the conveyance roller pair 21. The conveyance roller pair 21 further conveys the recording paper 3 in the forward direction. The paper edge sensor 22 a detects the leading edge of the recording paper 3 and inputs a detection signal to the control unit 47. The control unit 47 controls the transport position of the recording paper 3 based on the rotation amount of the transport motor 15 after the detection signal of the paper end sensor 22 is input.

  The controller 47 causes the recording motor 3 to convey the recording paper 3 in the forward direction by a predetermined interval. When the conveyance of the recording paper 3 is stopped, the control unit 47 controls the motor driver 59 to rotate the carriage motor 29 and move the carriage 27 in the main scanning direction. The control unit 47 detects the position of the carriage 27 by the encoder 62. The gate array 51 reads Y, M, C, and K drive data from the DRAM 50 and sends them to the head driver 57. The head driver 57 drives each inkjet head 33 based on each drive data, and discharges each ink of Y, M, C, K from each inkjet head 33 toward the 1st surface 3a.

  The first image 69 is recorded on the first surface 3a of the recording paper 3 by intermittent conveyance of the recording paper 3 in the forward direction and ink ejection when the conveyance is stopped. As shown in FIG. 6A, in the first image 69, first, the tip half region 69a is recorded on the first surface 3a. Next, as shown in FIG. 5B, the rear end half region 69b is recorded on the first surface 3a. Thus, the left and right directions of the first image 69 are recorded in the initial state orientation corresponding to the forward direction and the reverse direction of the recording paper 3.

  The recording paper 3 on which the first image 69 is recorded is discharged to the paper discharge tray 36 by the paper discharge roller pair 37. Based on the drying time read from the DRAM 50, the ink on the first surface 3 a is dried on the paper discharge tray 36. Since the drying time is calculated based on the amount of ink droplets applied to the first surface 3a, there is no wasted time. Further, the drying time is calculated so that the recording time of the rear end side half area 69b is used as a part of the drying time of the front end side half area 69a having a large amount of ink droplet ejection. This is shorter than when recording is started from a small rear end half area 69b. Note that the nipping of the recording paper 3 by the paper discharge roller pair 37 is not released while waiting for the drying time.

  After the drying time has elapsed, the control unit 47 rotates the transport motor 15 in the reverse direction to that during paper feeding, and transports the recording paper 3 in the reverse direction. Simultaneously, the 1st switching guide 43 and the 2nd switching guide 44 are moved to the inversion position shown with a broken line. The recording paper 3 conveyed in the reverse direction is fed into the loop-shaped conveyance path 40 by the first switching guide 43 and conveyed by the reverse roller pair 41, 42. The recording paper 3 is guided by the second switching guide 44 and fed into the paper feed path 19 again. Since the recording paper 3 in the paper feed path 19 has its front and back surfaces reversed by the recording paper reversing unit 9, the second surface 3b faces upward.

  The controller 47 reads the second recording data and performs data conversion in the same manner as when recording the first image 69 on the first surface 3a. The control unit 47 causes the recording unit 7 to record the second image 76 that is an image of the second recording data on the second surface 3b while conveying the recording paper 3 in the forward direction by the conveying unit 6. As shown in FIG. 6C, the second image 76 is recorded on the recording paper 3 so that the first image 69 has the same vertical direction. The recording paper 3 on which the second image 76 is recorded is discharged to the paper discharge tray 36.

  Next, a case where the second double-side recording process is selected by the recording control unit 72 will be described according to the flowchart of FIG. The drying time calculation unit 73 calculates the drying time as in the first double-sided process, and stores it in the DRAM 50.

  The controller 47 rotates the first image 69 recorded on the first surface 3a by 180 °. The rotation of the first image 69 may be performed with respect to the drive data of Y, M, C, and K, or after the first recording data is rotated, the drive data of Y, M, C, and K again. May be converted to Each drive data of the rotated first image 69 is stored in the DRAM 50.

  The controller 47 records the first image 69 on the first surface 3a while transporting the recording paper 3 in the forward direction, as in the first double-sided recording step. As shown in FIG. 7A, in the first image 69, a rear end side half area 69b in which the top and bottom are reversed first is recorded on the first surface 3a. Next, as shown in FIG. 5B, the front end side half area 69a is recorded on the first surface 3a. As a result, the first image 69 is recorded on the recording paper 3 while being rotated by 180 °.

  After the elapse of the drying time, the control unit 47 conveys the recording paper 3 in the reverse direction and causes the recording paper reversing unit 9 to invert it. The drying time of the second double-sided recording process is also calculated based on the ink droplet ejection amount as in the first double-sided recording process and using the recording time as part of the drying time. Shorter than the ink jet recording apparatus.

  After the reversal of the recording paper 3, the control unit 47 transports the recording paper 3 in the forward direction and records the second image 76 on the second surface 3b by rotating it 180 °, as in the first double-side recording process. As shown in FIG. 7C, the second image 76 is recorded on the recording paper 3 such that the first image 69 has the same vertical direction. The recording paper 3 is discharged to the paper discharge tray 36.

  As described above, since the first image 69 is recorded from the region where the ink droplet ejection amount is large in both the first double-sided recording step and the second double-sided recording step, the drying time can be shortened. Thereby, the time required for double-sided recording can be shortened.

  Some recording papers have a predetermined image recording direction. For example, a postcard, which is a standard paper, has a recording direction for the name, and the communication surface on the back side of the address needs to be recorded in an orientation that matches the name. The present invention can reduce the drying time even in the case where double-sided recording is performed on a standard paper whose image recording direction is determined, as in the above-described embodiment. Hereinafter, double-sided recording on a standard sheet will be described.

  In the present embodiment, similarly to the above-described embodiment, the first droplet 69 is divided into the front end side half region 69a and the rear end side half region by the ink droplet ejection amount acquisition circuit 66, and the front end side ink droplet ejection amount A and the rear side are divided. The end side ink droplet ejection amount B is acquired. Further, the recording control unit 72 compares the front-side ink ejection amount A and the rear-side ink ejection amount B, and performs duplex recording using either the first duplex recording step or the second duplex recording step. I have decided. The recording control unit 72 selects the first double-sided recording step when the front end side ink droplet ejection amount A is larger than the rear end side ink droplet ejection amount B, and the front end side ink droplet ejection amount A is equal to the rear end side ink droplet ejection. When the amount is smaller than the amount B, the second double-side recording process is selected.

  The first double-sided recording process of this embodiment is the same as that of the above-described embodiment shown in FIG.

  As shown in FIG. 11, in the second double-sided recording process of the present embodiment, the control unit 47 transports the recording paper 3 supplied from the paper feeding unit 5 in the forward direction by the transport roller pair 21 to record an image. Without being performed, the recording unit 7 is passed, and the paper is discharged onto the paper discharge tray 36 by the paper discharge roller pair 37. Note that the sandwiching of the recording paper 3 by the paper discharge roller pair 37 is not released.

  The control unit 47 conveys the recording paper 3 in the reverse direction by the paper discharge roller pair 37 and the conveyance roller pair 21, and detects the leading end (the right end in FIG. 12) of the recording paper 3 by the paper edge sensor 22b. The control unit 47 detects the transport position of the recording paper 3 based on the rotation amount of the transport motor 15 after the detection of the recording paper 3 by the paper edge sensor 22b. The recording unit 7 records the first image 69 on the first surface 3a of the recording paper 3 conveyed in the reverse direction.

  As shown in FIG. 12A, in the first image 69, the rear end half area 69b is first recorded. Next, as shown in FIG. 5B, the front end side half area 69a is recorded. During the conveyance in the reverse direction, the first switching guide 43 and the second switching guide 44 are stopped at the paper feeding position. That is, the recording paper 3 is conveyed straight along the guide member 18 without being inserted into the recording paper reversing unit 9. As a result, it is possible to prevent the ink adhering to the first surface 3a from coming into contact with the recording paper reversing unit 9 to disturb the image.

  After the recording of the first image 69 is completed, the control unit 47 transports the recording paper 3 in the forward direction again and discharges it to the paper discharge tray 36, and waits for the drying time. The controller 47 transports the recording paper 3 in the reverse direction again after the drying time has elapsed. In this reverse conveyance, the first switching guide 43 and the second switching guide 44 are moved to the reversal position, and the recording paper 3 is fed into the recording paper reversing unit 9. The recording paper 3 whose front and back surfaces are reversed by the recording paper reversing unit 9 is fed into the paper feed path 19 with the second surface 3b facing upward.

  The controller 47 records the second image 76 on the second surface 3b while transporting the recording paper 3 in the forward direction as in the first double-sided recording step of the above embodiment. As shown in FIG. 12C, since the second image 76 is recorded on the second surface 3b in the initial state, the direction of the image coincides with the first image 69.

  As described above, in the second double-sided recording process of the present embodiment, recording can be started from the rear end in the forward direction without rotating the first image 69. As a result, the drying time of the ink on the first surface can be optimally set and shortened even in double-sided recording on a standard paper. Note that a procedure for passing the recording paper 3 under the recording unit 7 before and after the recording of the first image 69 is necessary. However, since the drying time of an image with a large amount of ink droplets is longer, the double-side recording time is longer. Can be shortened.

  In each of the embodiments described above, the first image 69 is recorded on the first surface 3 a of the recording paper 3 and the second image 76 is recorded on the second surface 3 b, but ink ejection of the first image 69 and the second image 76 is performed. Depending on the droplet amount, the images recorded on the first surface 3a and the second surface 3b may be interchanged so that an image with a small ink droplet amount is recorded as the first image. Hereinafter, this embodiment will be described.

  As shown in the flowchart of FIG. 13, at the start of double-sided recording, the data array 52 reads the first recording data and the second recording data. Data conversion is performed by the data conversion circuit 65, and drive data is stored in the DRAM 50. The ink droplet ejection amount acquisition circuit 66 acquires the first ink droplet ejection amount A1 of the first image 69 and the second ink droplet ejection amount B1 of the second image 76. The recording control unit 72 compares the first ink droplet ejection amount A1 with the second ink droplet ejection amount B1.

  When the first ink droplet ejection amount A1 is smaller than the second ink droplet ejection amount B1, the first image 69 is recorded on the first surface 3a, and the second image 76 is recorded on the second surface 3b. As in the above embodiments, the image recording direction or the recording paper conveyance direction at the time of recording can be switched based on the leading edge ink ejection amount A and the trailing edge ink ejection amount B of the first image 69. preferable.

  When the first ink droplet ejection amount A1 is larger than the second ink droplet ejection amount B1, the first image 69 and the second image 76 are interchanged, and the second image 76 is recorded on the first surface 3a. The first image 69 is recorded on the second surface 3b. At this time, as in the above embodiments, the recording direction of the image or the conveyance of the recording paper at the time of recording is based on the leading edge ink ejection amount A and the trailing edge ink ejection amount B of the first image 69. It is preferable to switch the direction.

  Thus, if the first image 69 and the second image 76 are interchanged according to the ink droplet ejection amount, an image with a small ink droplet ejection amount is always recorded on the first surface 3a. Thereby, compared with the case where the 1st image 69 and the 2nd image 76 are not replaced, since the drying time of the 1st surface 3a becomes short, double-sided recording time can be shortened.

  In the above-described embodiment, the ink droplet ejection amounts of the front end side half region 69a and the rear end side half region 69b are compared. However, the size of the maximum region of ink droplet ejection amount may be compared. For example, the maximum region of the ink droplet ejection amount is a region where the ink droplet ejection amount per unit area is a predetermined value or more. The drying time can be set in view of the nature of the ink that is difficult to dry when many droplets are locally ejected.

  Further, it is not always necessary to change the orientation of the image or the conveyance direction of the recording paper during recording after the ink droplet ejection amount is compared. For example, from the difference between the amount of ink ejected on the front end and the amount of ink ejected on the rear end, a threshold value that can shorten the drying time when the image orientation or the recording paper transport direction is switched is obtained. deep. If the difference between the ink ejection amount at the front end and the ink ejection amount at the rear end is equal to or less than the threshold value, the effect is small even if the orientation of the image or the recording paper transport direction during recording is switched. It is also possible to record an image without it.

  In each of the above embodiments, the serial type ink jet recording apparatus that performs recording by moving the ink jet head in the main scanning direction has been described as an example. However, a line that performs recording with an ink jet head having a length corresponding to the width of the recording paper. The present invention can also be applied to a type inkjet recording apparatus.

It is the schematic which shows the structure of an inkjet recording device. It is a block diagram which shows the electric constitution of an inkjet recording device. It is a functional block diagram of a control part. It is explanatory drawing which shows an example of a 1st image. It is explanatory drawing which shows an example of a 2nd image. It is explanatory drawing which shows the recording procedure by a 1st double-sided recording process. It is explanatory drawing which shows the recording procedure by a 2nd double-sided recording process. It is a flowchart which shows the procedure of double-sided recording. It is a flowchart which shows the procedure of a 1st double-sided recording process. It is a flowchart which shows the procedure of a 2nd double-sided recording process. It is a flowchart which shows the recording procedure by another 2nd double-sided recording process. It is explanatory drawing which shows the recording procedure by another 2nd double-sided recording process. It is a flowchart which shows the procedure which interchanges a 1st image and a 2nd image according to the comparison result of the amount of ink droplets.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Inkjet recording device 3 Recording paper 3a 1st surface 3b 2nd surface 5 Paper feed part 6 Conveyance part 7 Recording part 8 Paper discharge part 9 Recording paper inversion part 47 Control part 48 MPU
51 Gate Array 65 Data Conversion Circuit 66 Ink Drop Amount Acquisition Circuit 69 First Image 69a Front Side Half Area 69b Rear End Side Half Area 72 Recording Control Unit 73 Drying Time Calculation Unit 76 Second Image

Claims (8)

A first image is recorded by ejecting ink droplets onto the first surface of the recording medium being transported in the forward direction, and the front and back surfaces of the recording medium are reversed after the ink adhering to the first surface is dried. In the ink jet recording apparatus for recording the second image by transporting the recording medium in the forward direction again and discharging the ink droplets onto the second surface of the recording medium.
The first image is divided into the front end half area and the rear end half area in the forward direction, and the front side ink droplet ejection amount, which is the amount of ink droplets necessary for recording the image in each area, An ink droplet amount acquisition means for acquiring a trailing edge side ink droplet amount;
The front-side ink droplet ejection amount is compared with the rear-end side ink droplet ejection amount, and when the front-end side ink droplet ejection amount is smaller than the rear-end side ink droplet ejection amount, An ink jet recording apparatus comprising: a recording control unit that rotates two images by 180 ° and records the images on the first surface and the second surface. A first image is recorded by ejecting ink droplets onto the first surface of the recording medium being transported in the forward direction, and the front and back surfaces of the recording medium are reversed after the ink adhering to the first surface is dried. In the ink jet recording apparatus for recording the second image by transporting the recording medium in the forward direction again and discharging the ink droplets onto the second surface of the recording medium.
The first image is divided into a front end side half region and a rear end side half region in the forward direction, and a front end side ink droplet ejection amount that is a droplet amount of the ink necessary for recording in each region, and a rear end Ink droplet ejection amount acquisition means for acquiring the side ink droplet ejection amount;
The front-end side ink droplet ejection amount is compared with the rear-end side ink droplet ejection amount. When the front-end side ink droplet ejection amount is smaller than the rear-end side ink droplet ejection amount, the recording medium is moved in the forward direction. An ink jet recording apparatus comprising: a recording control unit configured to convey the first image on the first surface by conveying in a reverse direction opposite to the first side.   The ink droplet ejection amount acquisition unit acquires a first ink droplet ejection amount and a second ink droplet ejection amount necessary for recording the first image and the second image, and the recording control unit includes the first ink droplet ejection amount. Comparing the first ink droplet ejection amount and the second ink droplet ejection amount, when the first ink droplet ejection amount is larger than the second ink droplet ejection amount, the first image and the second image are exchanged. The inkjet recording apparatus according to claim 1 or 2, wherein   A drying time calculation unit is provided for calculating a drying time for drying the ink attached to the first surface based on the leading edge ink droplet ejection amount and the trailing edge ink droplet ejection amount. The ink jet recording apparatus according to claim 1. A first image is recorded by ejecting ink droplets onto the first surface of the recording medium, the recording medium is inverted after the ink on the first surface is dried, and the ink is applied to the second surface of the recording medium. In an inkjet recording method for recording a second image by discharging droplets,
The first image is divided into a front end half region and a rear end half region in the forward direction in which the recording medium is conveyed, and the front end side is the amount of ink droplets necessary for recording the image in each region An ink ejection amount acquisition step of acquiring an ink ejection amount and a rear end side ink ejection amount;
A comparison step of comparing the leading-end side ink ejection amount and the trailing-end side ink ejection amount;
When the leading side ink droplet ejection amount is larger than the trailing edge side ink droplet ejection amount, the first image is recorded on the first surface while the recording medium is transported in the forward direction; A first double-sided recording step of recording the second image on the second surface while reversing the recording medium in the forward direction after reversing;
When the leading edge ink droplet ejection amount is smaller than the trailing edge ink droplet ejection amount, the first image is rotated by 180 ° and recorded on the first surface while the recording medium is conveyed in the forward direction. And a second double-sided recording step in which the second image is rotated by 180 ° and recorded on the second surface while the recording medium is conveyed in the forward direction again after the recording medium is reversed. Inkjet recording method. A first image is recorded by ejecting ink droplets onto the first surface of the recording medium, the recording medium is inverted after the ink on the first surface is dried, and the ink is applied to the second surface of the recording medium. In an inkjet recording method for recording a second image by discharging droplets,
In the forward direction in which the recording medium is conveyed, the first image is divided into a front end side half area and a rear end side half area, and the front end is the amount of ink droplets necessary for recording the image in each area. An ink ejection amount acquisition step of acquiring a side ink ejection amount and a rear end side ink ejection amount;
A comparison step of comparing the leading-end side ink ejection amount and the trailing-end side ink ejection amount;
When the leading side ink droplet ejection amount is larger than the trailing edge side ink droplet ejection amount, the first image is recorded on the first surface while the recording medium is transported in the forward direction; A first double-sided recording step of recording the second image on the second surface while reversing the recording medium in the forward direction after reversing;
When the leading-end ink ejection amount is smaller than the trailing-end ink ejection amount, the first image is transferred to the first surface while transporting the recording medium in the reverse direction opposite to the forward direction. An ink jet recording method comprising: a second double-sided recording step of recording and recording the second image on the second surface while transporting the recording medium in the forward direction after the recording medium is reversed. .   Prior to the ink droplet ejection amount acquisition step, a first ink droplet ejection amount and a second ink droplet ejection amount necessary for recording the first image and the second image are acquired, and the first ink droplet ejection amount is obtained. An image replacement step of comparing the first image and the second image when the first ink droplet deposition amount is larger than the second ink droplet ejection amount. The ink jet recording method according to claim 5, wherein the ink jet recording method is provided.   A drying time calculating step of calculating a drying time for drying the ink adhering to the first surface based on the leading edge side ink droplet amount and the trailing edge side ink droplet amount is provided. The ink jet recording method according to claim 5.

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